Burning-portland cement.



F. L. Woons a; M. BOYD'.

BURNING PORTLAND CEMENT. APPLIUATION FILED PERM, 1909.

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aqcooooo UNITED l ENT oFn1joE.-

FRED LEROY lOODE,` AND MERLIN BOYD, OF IOLA, KANSAS, ASSIGNORS TO HUNT ENGL NEERING COMPANY, OF 1011A, KANSAS, A CORPORATION.

BURNING PORTLAND CEMENT. la.'

Specification of Letters Patent.- lutgnted Ffh, 2S, 1911,'

Application tiled February 27', 1909. Serial No. 480,378. Y

To alliwhom itima'y concern:

Y Be it known that we, Fano L. lVoons and MERLIN Born, citizens of the United States, 'residing at lola, in the county of Allen, State of Kansas, have invented anew and useful Improvement in Burning Portland Cement, of which the following is a specifi cation.

This invention relates to a process of burning .cement material.

Heretofore, so far as we are aware, ce nient. materials have been burned 'in rotary kilns under subatinospheric conditions due to the draft'utethods eznployeifl. le have discovered that by positively feeding air under siiperatluospheric pressure to the r ing zone of the kilniu sulicient quantities to support complete combustion and to maintain supcratmospheric pressure in the fiinig zone. -and by lnaintainincY betu'eenthe tiring zone and thc stack a zone ot' kiln gases undersuperatniospherio pressure, and by utili-zing this zone o'l kiln trol the position of the tiring retardii'lg the escape of kiln gases at the stack, thereby increasing the time of contact of the hot kiln gases with theV raw inaterials and causing 'the operation of the kiln to be independent of atin'tosi iheric comlitions the effective intensity of the tiring zone is increased and n'iaintained and the cement material reaches the firing zone in proper condition, thereby ln'oducing a quick, thor ough, inciaient fusion ofthe cement 1naterial whiclh results in a clinker Athat is uniform in size and grade, yxsily ground and perfectly sound.' Ve have also discovered that by means of onl.' method, the daily output of a rotary kiln is almost doubled and considerably less fuel per barrel is consumed than is i'leccssary 'when using the saine kiln in the ordinary manner.-

The invention may be carried out with various kinds of fuel such for example as gaseous or liquid fuel or tine coal .or the like.

Vhile usually it is advantageous -to maintain positive pressure throughout the length of the kiln, this does not preclude the use of natural, that is stack draft, or forced draft at the stack end of the kiln to aid in discharging the waste gases from the kiln, but even under such corulitions there is a positive pressure throughout the ring zone and beyond. The invention will be best gases to con-v zone and by..

' of the process.

ln the drawings: the ligure is a 4longlgitndinal section with. parts broken away of a kiln adapted to the purposes of the present invention. Y

Referring to the draw-ing there is shown Va kiln 1 which inay be of the usual rotary type employed in. the manufacture of ce ment and consequently needs no speeitic'description. At the inlet end of the kiln there is inrovided a stack 2 and at the delivery end of the kiln there is provided a'housing 7:3. yWithin the stack 2 mounted a daniper l controlled by strands 5 extending over suitable pulleys t5 and through. guides 7 to the discharge end of the stack where a lever 8 is provided and is connected to the strands 5 so that by nmving the lever about its pivotV the damper L1 may be regulated as desired. A stand t) is provided for the support of the lever 8 and on this stand is a rack segment 1G while the lever carries a hand latch 1l adapted to engage between the teeth of the segment l() and .so lock the lerer'in adjusted y -pnt of the blower irrespective of its speed,

the intake is provided with a valve structure 12 which is preferably of the iris diaphragm type. A conduit 13 leads from the blower and has an extension 14 entering the housing 3 in position to discliarge into the kiln preferably' in substantially the central longitudinal axis thereof. The conduit 13 vand end 1l are made perfectly straight and of sufficient diameter to cut down the friction of the air and fuel particles thereon to a mnnnuun and yet- 'iernntthe velocity neces-v sary to deliver u sulticient-volume of Air (o the kiln to convey the mixture to a completo.

,conduit 18. If greater velocity of the fue] blast be needed on. the kiln eide then the dinphragni valve 1.4 is contracted and thel penetration of the-fuel blast and llame into the kiln increased because of the' increased velocity of the blast due to the decree. opening in the valve. (if course, increasing the opening through the valve le lowers the Velocity of the blast correspondingly.

The burning mixture enters the kiln pref- Y erably in the longitudinal exis tlfiereof and extends along the length of the kiln until it impinges againstthe. zone or cushionv of gases therein, which cushion is made u 'i of the evaporation of moisture, if present, rom the green material, the given oif during the eelcinng operation. end the gaseous products of combustion from theflnme, the incoming fuel under pressure serving to continuously force out the kiln :troniA the stack against the'throttling action of the demper 4 while the zone of kiln gases de termining the extent. of 'the flume remains substantially constantfor the seme conditions of throttling oy the demper 4l. end the pressure of the incoming air und fuel niek-- ing up' the self-burning mixture at the extension lll.

The resistance offered by the zone or rushion o kiln gases tends to spread out the llame until it brought into contact with the Walls ofthe vkiln and 'with the material traveling along the seine toward the diecharge end.- The operator hy watching the fire can readily control the penetra-tion ot thel flume either by controlling the velocity of the incoming blast or the density ot the cushion or zone of kiln gases. Under very-- ing-loads this causes the thune to diverge :it such an angle thnt it .for a proper hui-ning; icone. n'hieh is independent ol the stuck ior conibustion purposes, permits the kiln operation to he unaiieetcd hy atmospheric conditions.

This: muy oe explained hy ne furet. that the rapid evolution of rurlmn ilioxiiljgivrn oli' lo.: the ruu' umicrzzl in progression through the kiln 'fortes strikes the lining und l the material in progress through the kiln This nu-.tlio l,

the mail] part of the livie heut toward the top of the kiln (1o-such a ce us for instance is indicated at 15. Thi-'increased pressure nt the top causes the rebound und consequent change of directliiii of the fuel purtieles in the upper pertrof the Haine und this purt of the flume, therefore, tends to lup buck ,townrd the frontof the housing 3. At the zone indicated by the numeral 1G there is just enough pressure to balance the atmospheric pressure While alt the Zone indicnted by the runner-al1? there is :1 positive pressure. )bservetions of the conditions in these parts will ldetermine the nearest to the most economical position of the cushion.

The burning of the fuel mixture under compression, that is under e positive pressure above atmospheric pressure, or as it may he termed compressionul burning, results in u rapid :requirement of an intense heut in nu easily .coi-itrollable zone for the calcinui'ion and incipient fusion of the clinker. It offers ell the conditions of perr'ect mirth-tr., greatest effective temperature and inten. j, thorough diffusion, und that sutl'usion which resulte from the condition of pr 'ure in the kiln which leads ma rapid und. intimate mingling of fuel particles and nir and the iionsequent quick intense combustion, The method of the present invention puts [he controland regulation of the quality und qunntitynf the fire completely in the lui-nds of the operator und reduces the stuck to its proper function, that is, en out let. for Waste grises end for the regulation of hihi pressure. I

Pressure eux-vee taken from kilns while operated under-the compressionel system of the present, ,invention show that goed result-s are obtained hy operating the kiln under e present-enf approximately three and one half inches of water at the discharge or tiringeud 'of `the kiln, this pressure curve d ropiiingr to about one inch of water at a point twenty feet from the discharge end oi" the kiln und dropping to one-half inch at' u point forty feet inside ol the kiln, and he# coming u negative pressure :1t e. point op! pr xiuuitoly seventy-live ieetfrom the diS- chiarire und ot' the kiln. und, in cose of u kiln exceeding seventy-live toet in length7 wrmuiinuinp; :i negative or sulmlmospheri'e pressure Jfrom there lo the stuck end of the kiln. ll' the kiln he seventy or seventy-live 'Feet zu length the superal'mospherlc pressure will extend 'roui (he disohurge cud to the stuck. .Ylmeovcr-` in kilns exceeding seventy-4 live l'eel. the positive pressure muy be mainl tuiued entirely to the stuck hy increueiuir Observation luis shown that the density ol' i this divergent und retinrdml thune is grenier f et the top et the kiln.

vromllw dist-longe cuil und is thus under 4the iri'nn; zone usually-- loll'r feet into ihn kiln.,

u suprrzxlinospherie pressure of from three und one-half inches :it the discharge end to three quarters or .fine-half of un inch at its inner end. The cushion or zone of kiln under superatn'iospherie pressure will extend usually from the inner end of the tiring zone to n point seven-ty or seventyfive feet `from the discharge end of the kiln und its pressure will Vcurve from three quarters or one-half of un inch at, its outer end to atmospheric pressure at its inner end,

What is claimed is:

l. method ofI burning cement which consi ts in feeding fuel into a cement kiln, feeding nir under pressure in suicient quantities to support complete combustion of said fuel, mnd maintaining superetmos-Y pheric pressure throughout the' clinkering zone. A I

2. A niiethody of burning cement which eonsists 'in feeding fuel into a cement kiln= feeding `nir under pressure in sufficient quantities to support complete 'combustion of suid fuel, und maintaining superatmospheiirf pressure thrpughout the tiring zone.

2l. A method of burning cement which emisists in feeding fuel into a cement kiln,

feeding nir under pressure .in sutlicientA quantities to Vsupport complete combustion of said fuel, lnnintwining superatmospheric pressure in the tiring zone, und cbntrolling the position of the firingzone hy e zone of kiln gases maintained at supcratlnospheric pressure hctwoeii the tiringfzone and the stack.

'4. A method of burning cement which consists in feeding fuel into a cement kiln, feeding air under pressure in sutlicient quantities to support complete combustion of said fuel, maintaining supcratmospheric pressure in the tiring zone, und returding the escupe of the kiln gases, whereby un increased time of Contact with the raw material is obtained and the operation of the kiln is caused to be independent of atmospheric conditions.

5. A. method of' burning cement lwhich 

